This post is one of ten appearing in the series 10 Ways To Improve Your Landscape Photography.
You may have heard of Golden Hour, which is the time around sunrise and sunset. The reason it's called Golden Hour should be obvious from the effect the sun at this time has on the sky and the land. The light is generally quite warm in colour (hence golden) and diffuse (even). This has a few effects that are beneficial to the photographer:

The diffuse light softens and lighten shadows and reduces highlights which decreases the contrast range of the scene, making it easier to capture detail from the shadows all the way to the highlights.

the sky often takes on wonderful colours that adds interest to the scene and the land glows as it bathes in warm light

shadows are longer, adding texture and depth to a scene by showing the contours of the landscape

By contrast (pun intended!) a scene lit by the mid day sun will have a lot of contrast (very deep, black shadows v very bright, directly illuminated objects), short shadows providing little depth and the colour of the light being very "normal" hence unremarkable.

Whilst it's possible to create stunning images during the day, your chances of capturing beautiful images increase dramatically at the start and the end of the day. I would say that 80% of my images are made at the extremes of the day. I saw a massive improvement in my results when I stopped expecting to be able to shoot great images at any point in the day.

The Golden Hour can actually be longer or shorter based on the time of year, weather, geography, etc. However it provides a useful guide to when you need to be in location. Obviously being in location at these times can be tricky, especially for sunrise in Summer which was at 4.38am at its height where I live.

Taking into account travel, walking to location, etc that would mean getting up at about 2-2.30am which is tough. This amongst other reasons is why many photographers regard Summer as their least favourite season for shooting. However during other seasons and if you have the discipline to go out at these times then you will be richly rewarded.

One final thought is that we often think shooting at Golden Hour means taking pictures of sunrises and sunsets - I certainly did for a long time! What we really value at this time is the quality of the light moreso than the opportunity to shoot the sun. Rather than facing the sun try turning around to look at the landscape as the sun casts beautiful light onto it and the sky above it. That's the real gold.